/**
 @file  enet.h
 @brief ENet public header file
*/
#ifndef __ENET_ENET_H__
#define __ENET_ENET_H__

#ifdef __cplusplus
extern "C"
{
#endif

#include <stdlib.h>

#ifdef WIN32
#include "enet/win32.h"
#else
#include "enet/unix.h"
#endif

#include "enet/types.h"
#include "enet/protocol.h"
#include "enet/list.h"
#include "enet/callbacks.h"

#define ENET_VERSION_MAJOR 1
#define ENET_VERSION_MINOR 2
#define ENET_VERSION_PATCH 5
#define ENET_VERSION_CREATE(major, minor, patch) (((major)<<16) | ((minor)<<8) | (patch))
#define ENET_VERSION ENET_VERSION_CREATE(ENET_VERSION_MAJOR, ENET_VERSION_MINOR, ENET_VERSION_PATCH)

	typedef enet_uint32 ENetVersion;

	typedef enum _ENetSocketType
	{
		ENET_SOCKET_TYPE_STREAM = 1,
		ENET_SOCKET_TYPE_DATAGRAM = 2
	} ENetSocketType;

	typedef enum _ENetSocketWait
	{
		ENET_SOCKET_WAIT_NONE = 0,
		ENET_SOCKET_WAIT_SEND = (1 << 0),
		ENET_SOCKET_WAIT_RECEIVE = (1 << 1)
	} ENetSocketWait;

	typedef enum _ENetSocketOption
	{
		ENET_SOCKOPT_NONBLOCK = 1,
		ENET_SOCKOPT_BROADCAST = 2,
		ENET_SOCKOPT_RCVBUF = 3,
		ENET_SOCKOPT_SNDBUF = 4,
		ENET_SOCKOPT_REUSEADDR = 5
	} ENetSocketOption;

	enum
	{
		ENET_HOST_ANY = 0,            /**< specifies the default server host */
		ENET_HOST_BROADCAST = 0xFFFFFFFF,   /**< specifies a subnet-wide broadcast */

		ENET_PORT_ANY = 0             /**< specifies that a port should be automatically chosen */
	};

	/**
	 * Portable internet address structure.
	 *
	 * The host must be specified in network byte-order, and the port must be in host
	 * byte-order. The constant ENET_HOST_ANY may be used to specify the default
	 * server host. The constant ENET_HOST_BROADCAST may be used to specify the
	 * broadcast address (255.255.255.255).  This makes sense for enet_host_connect,
	 * but not for enet_host_create.  Once a server responds to a broadcast, the
	 * address is updated from ENET_HOST_BROADCAST to the server's actual IP address.
	 */
	typedef struct _ENetAddress
	{
		enet_uint32 host;
		enet_uint16 port;
	} ENetAddress;

	/**
	 * Packet flag bit constants.
	 *
	 * The host must be specified in network byte-order, and the port must be in
	 * host byte-order. The constant ENET_HOST_ANY may be used to specify the
	 * default server host.

	   @sa ENetPacket
	*/
	typedef enum _ENetPacketFlag
	{
		/** packet must be received by the target peer and resend attempts should be
		  * made until the packet is delivered */
		ENET_PACKET_FLAG_RELIABLE = (1 << 0),
		/** packet will not be sequenced with other packets
		  * not supported for reliable packets
		  */
		ENET_PACKET_FLAG_UNSEQUENCED = (1 << 1),
		/** packet will not allocate data, and user must supply it instead */
		ENET_PACKET_FLAG_NO_ALLOCATE = (1 << 2)
	} ENetPacketFlag;

	struct _ENetPacket;
	typedef void (ENET_CALLBACK * ENetPacketFreeCallback) (struct _ENetPacket *);

	/**
	 * ENet packet structure.
	 *
	 * An ENet data packet that may be sent to or received from a peer. The shown
	 * fields should only be read and never modified. The data field contains the
	 * allocated data for the packet. The dataLength fields specifies the length
	 * of the allocated data.  The flags field is either 0 (specifying no flags),
	 * or a bitwise-or of any combination of the following flags:
	 *
	 *    ENET_PACKET_FLAG_RELIABLE - packet must be received by the target peer
	 *    and resend attempts should be made until the packet is delivered
	 *
	 *    ENET_PACKET_FLAG_UNSEQUENCED - packet will not be sequenced with other packets
	 *    (not supported for reliable packets)
	 *
	 *    ENET_PACKET_FLAG_NO_ALLOCATE - packet will not allocate data, and user must supply it instead

	   @sa ENetPacketFlag
	 */
	typedef struct _ENetPacket
	{
		size_t                   referenceCount;  /**< internal use only */
		enet_uint32              flags;           /**< bitwise-or of ENetPacketFlag constants */
		enet_uint8 *             data;            /**< allocated data for packet */
		size_t                   dataLength;      /**< length of data */
		ENetPacketFreeCallback   freeCallback;    /**< function to be called when the packet is no longer in use */
	} ENetPacket;

	typedef struct _ENetAcknowledgement
	{
		ENetListNode acknowledgementList;
		enet_uint32  sentTime;
		ENetProtocol command;
	} ENetAcknowledgement;

	typedef struct _ENetOutgoingCommand
	{
		ENetListNode outgoingCommandList;
		enet_uint16  reliableSequenceNumber;
		enet_uint16  unreliableSequenceNumber;
		enet_uint32  sentTime;
		enet_uint32  roundTripTimeout;
		enet_uint32  roundTripTimeoutLimit;
		enet_uint32  fragmentOffset;
		enet_uint16  fragmentLength;
		enet_uint16  sendAttempts;
		ENetProtocol command;
		ENetPacket * packet;
	} ENetOutgoingCommand;

	typedef struct _ENetIncomingCommand
	{
		ENetListNode     incomingCommandList;
		enet_uint16      reliableSequenceNumber;
		enet_uint16      unreliableSequenceNumber;
		ENetProtocol     command;
		enet_uint32      fragmentCount;
		enet_uint32      fragmentsRemaining;
		enet_uint32 *    fragments;
		ENetPacket *     packet;
	} ENetIncomingCommand;

	typedef enum _ENetPeerState
	{
		ENET_PEER_STATE_DISCONNECTED = 0,
		ENET_PEER_STATE_CONNECTING = 1,
		ENET_PEER_STATE_ACKNOWLEDGING_CONNECT = 2,
		ENET_PEER_STATE_CONNECTION_PENDING = 3,
		ENET_PEER_STATE_CONNECTION_SUCCEEDED = 4,
		ENET_PEER_STATE_CONNECTED = 5,
		ENET_PEER_STATE_DISCONNECT_LATER = 6,
		ENET_PEER_STATE_DISCONNECTING = 7,
		ENET_PEER_STATE_ACKNOWLEDGING_DISCONNECT = 8,
		ENET_PEER_STATE_ZOMBIE = 9
	} ENetPeerState;

#ifndef ENET_BUFFER_MAXIMUM
#define ENET_BUFFER_MAXIMUM (1 + 2 * ENET_PROTOCOL_MAXIMUM_PACKET_COMMANDS)
#endif

	enum
	{
		ENET_HOST_RECEIVE_BUFFER_SIZE = 256 * 1024,
		ENET_HOST_SEND_BUFFER_SIZE = 256 * 1024,
		ENET_HOST_BANDWIDTH_THROTTLE_INTERVAL = 1000,
		ENET_HOST_DEFAULT_MTU = 1400,

		ENET_PEER_DEFAULT_ROUND_TRIP_TIME = 500,
		ENET_PEER_DEFAULT_PACKET_THROTTLE = 32,
		ENET_PEER_PACKET_THROTTLE_SCALE = 32,
		ENET_PEER_PACKET_THROTTLE_COUNTER = 7,
		ENET_PEER_PACKET_THROTTLE_ACCELERATION = 2,
		ENET_PEER_PACKET_THROTTLE_DECELERATION = 2,
		ENET_PEER_PACKET_THROTTLE_INTERVAL = 5000,
		ENET_PEER_PACKET_LOSS_SCALE = (1 << 16),
		ENET_PEER_PACKET_LOSS_INTERVAL = 10000,
		ENET_PEER_WINDOW_SIZE_SCALE = 64 * 1024,
		ENET_PEER_TIMEOUT_LIMIT = 32,
		ENET_PEER_TIMEOUT_MINIMUM = 5000,
		ENET_PEER_TIMEOUT_MAXIMUM = 30000,
		ENET_PEER_PING_INTERVAL = 500,
		ENET_PEER_UNSEQUENCED_WINDOWS = 64,
		ENET_PEER_UNSEQUENCED_WINDOW_SIZE = 1024,
		ENET_PEER_FREE_UNSEQUENCED_WINDOWS = 32,
		ENET_PEER_RELIABLE_WINDOWS = 16,
		ENET_PEER_RELIABLE_WINDOW_SIZE = 0x1000,
		ENET_PEER_FREE_RELIABLE_WINDOWS = 8
	};

	typedef struct _ENetChannel
	{
		enet_uint16  outgoingReliableSequenceNumber;
		enet_uint16  outgoingUnreliableSequenceNumber;
		enet_uint16  usedReliableWindows;
		enet_uint16  reliableWindows[ENET_PEER_RELIABLE_WINDOWS];
		enet_uint16  incomingReliableSequenceNumber;
		enet_uint16  incomingUnreliableSequenceNumber;
		ENetList     incomingReliableCommands;
		ENetList     incomingUnreliableCommands;
	} ENetChannel;

	/**
	 * An ENet peer which data packets may be sent or received from.
	 *
	 * No fields should be modified unless otherwise specified.
	 */
	typedef struct _ENetPeer
	{
		ENetListNode  dispatchList;
		struct _ENetHost * host;
		enet_uint16   outgoingPeerID;
		enet_uint16   incomingPeerID;
		enet_uint32   sessionID;
		ENetAddress   address;            /**< Internet address of the peer */
		void *        data;               /**< Application private data, may be freely modified */
		ENetPeerState state;
		ENetChannel * channels;
		size_t        channelCount;       /**< Number of channels allocated for communication with peer */
		enet_uint32   incomingBandwidth;  /**< Downstream bandwidth of the client in bytes/second */
		enet_uint32   outgoingBandwidth;  /**< Upstream bandwidth of the client in bytes/second */
		enet_uint32   incomingBandwidthThrottleEpoch;
		enet_uint32   outgoingBandwidthThrottleEpoch;
		enet_uint32   incomingDataTotal;
		enet_uint32   outgoingDataTotal;
		enet_uint32   lastSendTime;
		enet_uint32   lastReceiveTime;
		enet_uint32   nextTimeout;
		enet_uint32   earliestTimeout;
		enet_uint32   packetLossEpoch;
		enet_uint32   packetsSent;
		enet_uint32   packetsLost;
		enet_uint32   packetLoss;          /**< mean packet loss of reliable packets as a ratio with respect to the constant ENET_PEER_PACKET_LOSS_SCALE */
		enet_uint32   packetLossVariance;
		enet_uint32   packetThrottle;
		enet_uint32   packetThrottleLimit;
		enet_uint32   packetThrottleCounter;
		enet_uint32   packetThrottleEpoch;
		enet_uint32   packetThrottleAcceleration;
		enet_uint32   packetThrottleDeceleration;
		enet_uint32   packetThrottleInterval;
		enet_uint32   lastRoundTripTime;
		enet_uint32   lowestRoundTripTime;
		enet_uint32   lastRoundTripTimeVariance;
		enet_uint32   highestRoundTripTimeVariance;
		enet_uint32   roundTripTime;            /**< mean round trip time (RTT), in milliseconds, between sending a reliable packet and receiving its acknowledgement */
		enet_uint32   roundTripTimeVariance;
		enet_uint16   mtu;
		enet_uint32   windowSize;
		enet_uint32   reliableDataInTransit;
		enet_uint16   outgoingReliableSequenceNumber;
		ENetList      acknowledgements;
		ENetList      sentReliableCommands;
		ENetList      sentUnreliableCommands;
		ENetList      outgoingReliableCommands;
		ENetList      outgoingUnreliableCommands;
		ENetList      dispatchedCommands;
		int           needsDispatch;
		enet_uint16   incomingUnsequencedGroup;
		enet_uint16   outgoingUnsequencedGroup;
		enet_uint32   unsequencedWindow[ENET_PEER_UNSEQUENCED_WINDOW_SIZE / 32];
		enet_uint32   disconnectData;
	} ENetPeer;

	/** Callback that computes the checksum of the data held in buffers [0..bufferCount-1] */
	typedef enet_uint32(ENET_CALLBACK * ENetChecksumCallback) (const ENetBuffer * buffers, size_t bufferCount);

	/** An ENet host for communicating with peers.
	  *
	  * No fields should be modified.

		@sa enet_host_create()
		@sa enet_host_destroy()
		@sa enet_host_connect()
		@sa enet_host_service()
		@sa enet_host_flush()
		@sa enet_host_broadcast()
		@sa enet_host_checksum()
		@sa enet_host_channel_limit()
		@sa enet_host_bandwidth_limit()
		@sa enet_host_bandwidth_throttle()
	  */
	typedef struct _ENetHost
	{
		ENetSocket           socket;
		ENetAddress          address;                     /**< Internet address of the host */
		enet_uint32          incomingBandwidth;           /**< downstream bandwidth of the host */
		enet_uint32          outgoingBandwidth;           /**< upstream bandwidth of the host */
		enet_uint32          bandwidthThrottleEpoch;
		enet_uint32          mtu;
		int                  recalculateBandwidthLimits;
		ENetPeer *           peers;                       /**< array of peers allocated for this host */
		size_t               peerCount;                   /**< number of peers allocated for this host */
		size_t               channelLimit;                /**< maximum number of channels allowed for connected peers */
		enet_uint32          serviceTime;
		ENetList             dispatchQueue;
		int                  continueSending;
		size_t               packetSize;
		enet_uint8          headerFlags;
		ENetProtocol         commands[ENET_PROTOCOL_MAXIMUM_PACKET_COMMANDS];
		size_t               commandCount;
		ENetBuffer           buffers[ENET_BUFFER_MAXIMUM];
		size_t               bufferCount;
		ENetChecksumCallback checksum;
		ENetAddress          receivedAddress;
		enet_uint8           receivedData[ENET_PROTOCOL_MAXIMUM_MTU];
		size_t               receivedDataLength;
		enet_uint32          totalSentData;               /**< total data sent, user should reset to 0 as needed to prevent overflow */
		enet_uint32          totalSentPackets;            /**< total UDP packets sent, user should reset to 0 as needed to prevent overflow */
		enet_uint32          totalReceivedData;           /**< total data received, user should reset to 0 as needed to prevent overflow */
		enet_uint32          totalReceivedPackets;        /**< total UDP packets received, user should reset to 0 as needed to prevent overflow */
	} ENetHost;

	/**
	 * An ENet event type, as specified in @ref ENetEvent.
	 */
	typedef enum _ENetEventType
	{
		/** no event occurred within the specified time limit */
		ENET_EVENT_TYPE_NONE = 0,

		/** a connection request initiated by enet_host_connect has completed.
		  * The peer field contains the peer which successfully connected.
		  */
		ENET_EVENT_TYPE_CONNECT = 1,

		/** a peer has disconnected.  This event is generated on a successful
		  * completion of a disconnect initiated by enet_pper_disconnect, if
		  * a peer has timed out, or if a connection request intialized by
		  * enet_host_connect has timed out.  The peer field contains the peer
		  * which disconnected. The data field contains user supplied data
		  * describing the disconnection, or 0, if none is available.
		  */
		ENET_EVENT_TYPE_DISCONNECT = 2,

		/** a packet has been received from a peer.  The peer field specifies the
		  * peer which sent the packet.  The channelID field specifies the channel
		  * number upon which the packet was received.  The packet field contains
		  * the packet that was received; this packet must be destroyed with
		  * enet_packet_destroy after use.
		  */
		ENET_EVENT_TYPE_RECEIVE = 3
	} ENetEventType;

	/**
	 * An ENet event as returned by enet_host_service().

	   @sa enet_host_service
	 */
	typedef struct _ENetEvent
	{
		ENetEventType        type;      /**< type of the event */
		ENetPeer *           peer;      /**< peer that generated a connect, disconnect or receive event */
		enet_uint8           channelID; /**< channel on the peer that generated the event, if appropriate */
		enet_uint32          data;      /**< data associated with the event, if appropriate */
		ENetPacket *         packet;    /**< packet associated with the event, if appropriate */
	} ENetEvent;

	/** @defgroup global ENet global functions
		@{
	*/

	/**
	  Initializes ENet globally.  Must be called prior to using any functions in
	  ENet.
	  @returns 0 on success, < 0 on failure
	*/
	ENET_API int enet_initialize(void);

	/**
	  Initializes ENet globally and supplies user-overridden callbacks. Must be called prior to using any functions in ENet. Do not use enet_initialize() if you use this variant. Make sure the ENetCallbacks structure is zeroed out so that any additional callbacks added in future versions will be properly ignored.

	  @param version the constant ENET_VERSION should be supplied so ENet knows which version of ENetCallbacks struct to use
	  @param inits user-overriden callbacks where any NULL callbacks will use ENet's defaults
	  @returns 0 on success, < 0 on failure
	*/
	ENET_API int enet_initialize_with_callbacks(ENetVersion version, const ENetCallbacks * inits);

	/**
	  Shuts down ENet globally.  Should be called when a program that has
	  initialized ENet exits.
	*/
	ENET_API void enet_deinitialize(void);

	/** @} */

	/** @defgroup private ENet private implementation functions */

	/**
	  Returns the wall-time in milliseconds.  Its initial value is unspecified
	  unless otherwise set.
	  */
	ENET_API enet_uint32 enet_time_get(void);
	/**
	  Sets the current wall-time in milliseconds.
	  */
	ENET_API void enet_time_set(enet_uint32);

	/** @defgroup socket ENet socket functions
		@{
	*/
	ENET_API ENetSocket enet_socket_create(ENetSocketType);
	ENET_API int        enet_socket_bind(ENetSocket, const ENetAddress *);
	ENET_API int        enet_socket_listen(ENetSocket, int);
	ENET_API ENetSocket enet_socket_accept(ENetSocket, ENetAddress *);
	ENET_API int        enet_socket_connect(ENetSocket, const ENetAddress *);
	ENET_API int        enet_socket_send(ENetSocket, const ENetAddress *, const ENetBuffer *, size_t);
	ENET_API int        enet_socket_receive(ENetSocket, ENetAddress *, ENetBuffer *, size_t);
	ENET_API int        enet_socket_wait(ENetSocket, enet_uint32 *, enet_uint32);
	ENET_API int        enet_socket_set_option(ENetSocket, ENetSocketOption, int);
	ENET_API void       enet_socket_destroy(ENetSocket);
	ENET_API int        enet_socketset_select(ENetSocket, ENetSocketSet *, ENetSocketSet *, enet_uint32);

	/** @} */

	/** @defgroup Address ENet address functions
		@{
	*/
	/** Attempts to resolve the host named by the parameter hostName and sets
		the host field in the address parameter if successful.
		@param address destination to store resolved address
		@param hostName host name to lookup
		@retval 0 on success
		@retval < 0 on failure
		@returns the address of the given hostName in address on success
	*/
	ENET_API int enet_address_set_host(ENetAddress * address, const char * hostName);

	/** Gives the printable form of the ip address specified in the address parameter.
		@param address    address printed
		@param hostName   destination for name, must not be NULL
		@param nameLength maximum length of hostName.
		@returns the null-terminated name of the host in hostName on success
		@retval 0 on success
		@retval < 0 on failure
	*/
	ENET_API int enet_address_get_host_ip(const ENetAddress * address, char * hostName, size_t nameLength);

	/** Attempts to do a reverse lookup of the host field in the address parameter.
		@param address    address used for reverse lookup
		@param hostName   destination for name, must not be NULL
		@param nameLength maximum length of hostName.
		@returns the null-terminated name of the host in hostName on success
		@retval 0 on success
		@retval < 0 on failure
	*/
	ENET_API int enet_address_get_host(const ENetAddress * address, char * hostName, size_t nameLength);

	/** @} */

	ENET_API ENetPacket * enet_packet_create(const void *, size_t, enet_uint32);
	ENET_API void         enet_packet_destroy(ENetPacket *);
	ENET_API int          enet_packet_resize(ENetPacket *, size_t);
	extern enet_uint32    enet_crc32(const ENetBuffer *, size_t);

	ENET_API ENetHost * enet_host_create(const ENetAddress *, size_t, enet_uint32, enet_uint32);
	ENET_API void       enet_host_destroy(ENetHost *);
	ENET_API ENetPeer * enet_host_connect(ENetHost *, const ENetAddress *, size_t);
	ENET_API int        enet_host_check_events(ENetHost *, ENetEvent *);
	ENET_API int        enet_host_service(ENetHost *, ENetEvent *, enet_uint32);
	ENET_API void       enet_host_flush(ENetHost *);
	ENET_API void       enet_host_broadcast(ENetHost *, enet_uint8, ENetPacket *);
	ENET_API void       enet_host_channel_limit(ENetHost *, size_t);
	ENET_API void       enet_host_bandwidth_limit(ENetHost *, enet_uint32, enet_uint32);
	extern   void       enet_host_bandwidth_throttle(ENetHost *);

	ENET_API int                 enet_peer_send(ENetPeer *, enet_uint8, ENetPacket *);
	ENET_API ENetPacket *        enet_peer_receive(ENetPeer *, enet_uint8 * channelID);
	ENET_API void                enet_peer_ping(ENetPeer *);
	ENET_API void                enet_peer_reset(ENetPeer *);
	ENET_API void                enet_peer_disconnect(ENetPeer *, enet_uint32);
	ENET_API void                enet_peer_disconnect_now(ENetPeer *, enet_uint32);
	ENET_API void                enet_peer_disconnect_later(ENetPeer *, enet_uint32);
	ENET_API void                enet_peer_throttle_configure(ENetPeer *, enet_uint32, enet_uint32, enet_uint32);
	extern int                   enet_peer_throttle(ENetPeer *, enet_uint32);
	extern void                  enet_peer_reset_queues(ENetPeer *);
	extern void                  enet_peer_setup_outgoing_command(ENetPeer *, ENetOutgoingCommand *);
	extern ENetOutgoingCommand * enet_peer_queue_outgoing_command(ENetPeer *, const ENetProtocol *, ENetPacket *, enet_uint32, enet_uint16);
	extern ENetIncomingCommand * enet_peer_queue_incoming_command(ENetPeer *, const ENetProtocol *, ENetPacket *, enet_uint32);
	extern ENetAcknowledgement * enet_peer_queue_acknowledgement(ENetPeer *, const ENetProtocol *, enet_uint16);
	extern void                  enet_peer_dispatch_incoming_unreliable_commands(ENetPeer *, ENetChannel *);
	extern void                  enet_peer_dispatch_incoming_reliable_commands(ENetPeer *, ENetChannel *);

	extern size_t enet_protocol_command_size(enet_uint8);

#ifdef __cplusplus
}
#endif

#endif /* __ENET_ENET_H__ */
